1. Field of the Invention
This invention relates to the preparation of highly efficient surfactants and their utilization in producing cellular foam materials, particularly isocyanurate and urethane foams. The surfactants can be prepared by reacting under free radical polymerization conditions (1) an unsaturated polyoxyalkylene adduct and (2) an esterified unsaturated dibasic acid ingredient, wherein unsaturated diester ingredient (2) either completely or partially comprises a fumarate diester.
2. Description of the Prior Art
It is known in the manufacture of cellular polymeric materials to utilize small quantities of various cell stabilizing additives, such as silicones, in order to improve the foam's cell quality. While the silicone surface active agents contribute to the production of foamed products having a combination of desirable properties, silicone surfactants are relatively expensive materials.
Another highly effective cellular foam stabilizer of the prior art is the capped reaction product of an alkoxylated amine and a copolymerizable mixture of dialkyl maleate and N-vinyl-2-pyrrolidinone or N-vinyl caprolactam, which is disclosed in U.S. Pat. No. 4,140,842. However, this foam stabilizer is also relatively expensive and has been found to consist of a complex mixture whose components must be separated from each other to realize their particularly desirable cellular foam stabilizing properties.
Moreover, it is now known that there can be used, as relatively inexpensive substitutes for silicone surfactants, the polyoxyalkylene/unsaturated diester reaction products which are disclosed in U.S. Pat. No. 4,365,024. Particularly useful surfactants of this patent are products derived from the free-radical initiated reaction between capped and uncapped polyoxyalkylene adducts and ditridecyl maleate. While these products have proved to be highly satisfactory in promoting the stabilization of many foams, they have been less efficient in certain difficult-to-stabilize urethane and isocyanurate foams.
It would accordingly be highly desirable to provide an improved surface active agent which would be relatively simple and inexpensive to produce, and have good foam stabilizing characteristics in even difficult-to-stabilize urethane and isocyanurate foams.